The effective control of weeds in fields in which agricultural crops are grown has been a continuing problem since farming began. Weed control measures have varied from cultivation to chemical herbicides. While providing weed control to varying degrees, each of the heretofore employed weed control measures have presented problems, disadvantages and deficiencies. For example, cultivation is time-consuming, expensive and results in soil erosion. Chemical herbicides present ecological problems by introducing toxic and sometimes non-biodegradable substances into the ecosystem.
Johnson grass (Sorghum halepense) is a weed that is sometimes difficult to control in agricultural crops because it is extremely hardy and propagates from both seeds and rizomes. Cultivation is therefore not very effective in the control of johnson grass. While certain chemical herbicides provide some measure of control, particularly in the seedling stage, these chemicals present problems from an ecological standpoint, as discussed above.
With the foregoing in mind, it is an object of the present invention to provide a biological method of controlling johnson grass and similar weeds in agricultural crops which is effective and which does not present ecological problems.